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    <title>artest</title>
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    <center>Scilab Function</center>
    <div align="right">Last update : April 1993</div>
    <p>
      <b>artest</b> -  arnold dynamical system</p>
    <h3>
      <font color="blue">Calling Sequence</font>
    </h3>
    <dl>
      <dd>
        <tt>artest(f_l,[odem,xdim,npts])  </tt>
      </dd>
      <dd>
        <tt>arnold(t,x)  </tt>
      </dd>
      <dd>
        <tt>iarf([a])  </tt>
      </dd>
    </dl>
    <h3>
      <font color="blue">Parameters</font>
    </h3>
    <ul>
      <li>
        <tt>
          <b>f_l</b>
        </tt>: can be "arnold" or arnold. It is the name of the external for the arnold system. If  <tt>
          <b>f_l</b>
        </tt> is set to "arnold" a Fortran coded version of the arnold system where a(1:6)=1  will be used and if <tt>
          <b>f_l</b>
        </tt> is set to arnold a Scilab coded version will be used .  <tt>
          <b>arnold</b>
        </tt> is a Scilab macro coding the Arnold system. This macro is loaded when calling <tt>
          <b>artest</b>
        </tt>.</li>
      <li>
        <tt>
          <b>iarf</b>
        </tt>: is used to fix the values of <tt>
          <b>a</b>
        </tt> in the Scilab coded case. <tt>
          <b>a</b>
        </tt> is a vector of size 6.</li>
      <li>
        <tt>
          <b>odem,xdim,npts</b>
        </tt>: are optional arguments. Their meaning and syntax can be found in the <tt>
          <b>portr3d</b>
        </tt>  help</li>
    </ul>
    <h3>
      <font color="blue">Description</font>
    </h3>
    <p>
    A call to the function <tt>
        <b>artest()</b>
      </tt> will interactively 
    display a phase portrait of  a the following dynamical system :</p>
    <pre>

      ydot(1)=a(1)*cos(y(2)) +a(2)*sin(y(3))
      ydot(2)=a(3)*cos(y(3)) +a(4)*sin(y(1))
      ydot(3)=a(5)*cos(y(1)) +a(6)*sin(y(2))
   
    </pre>
    <h3>
      <font color="blue">See Also</font>
    </h3>
    <p>
      <a href="portr3d.htm">
        <tt>
          <b>portr3d</b>
        </tt>
      </a>,&nbsp;&nbsp;<a href="../nonlinear/ode.htm">
        <tt>
          <b>ode</b>
        </tt>
      </a>,&nbsp;&nbsp;<a href="chaintest.htm">
        <tt>
          <b>chaintest</b>
        </tt>
      </a>,&nbsp;&nbsp;<a href="lotest.htm">
        <tt>
          <b>lotest</b>
        </tt>
      </a>,&nbsp;&nbsp;</p>
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